cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 13 results. Next

A028374 Numbers that have only curved digits {0, 3, 6, 8, 9} or digits that are both curved and linear {2, 5}.

Original entry on oeis.org

0, 2, 3, 5, 6, 8, 9, 20, 22, 23, 25, 26, 28, 29, 30, 32, 33, 35, 36, 38, 39, 50, 52, 53, 55, 56, 58, 59, 60, 62, 63, 65, 66, 68, 69, 80, 82, 83, 85, 86, 88, 89, 90, 92, 93, 95, 96, 98, 99, 200, 202, 203, 205, 206, 208, 209, 220, 222, 223, 225, 226, 228, 229, 230, 232, 233
Offset: 1

Views

Author

Greg Heil (gheil(AT)scn.org), Dec 11 1999

Keywords

Comments

From Bernard Schott, Mar 26 2023: (Start)
Previous name was: "Curved numbers: numbers that have only curved digits (0, 2, 3, 5, 6, 8, 9)"; but in fact, the curved numbers form the sequence A072960.
This sequence allows all digits except for 1, 4 and 7. (End)

Examples

			From _K. D. Bajpai_, Sep 07 2014: (Start)
206 is in the sequence because it has only curved digits 2, 0 and 6.
208 is in the sequence because it has only curved digits 2, 0 and 8.
2035689 is the smallest number having all the curved digits.
(End)
		

Crossrefs

Cf. A028373 (straight digits: 1, 4, 7), A072960 (curved digits: 0, 3, 6, 8, 9), A072961 (both straight and curved digits: 2, 5).
Combinations: A082741 (digits: 1, 2, 4, 5, 7), A361780 (digits: 0, 1, 3, 4, 6, 7, 8, 9).
Cf. A034470 (subsequence of primes).

Programs

  • Magma
    [n: n in [0..300] | Set(Intseq(n)) subset [0,2,3,5, 6,8,9] ]; // Vincenzo Librandi, Sep 19 2014
  • Maple
    N:= 3: S:= {0, 2, 3, 5, 6, 8, 9}: K:= S:
    for j from 2 to N do
         K:= map(t -> seq(10*t+s, s=S), K);
             od:
    print( K);  # K. D. Bajpai, Sep 07 2014
  • Mathematica
    f[n_] := Block[{id = IntegerDigits[n], curve = {0, 2, 3, 5, 6, 8, 9}}, If[ Union[ Join[id, curve]] == curve, True, False]]; Select[ Range[0, 240], f[ # ] & ]
    Select[Range[0, 249], Union[DigitCount[#] * {1, 0, 0, 1, 0, 0, 1, 0, 0, 0}] == {0} &] (* Alonso del Arte, May 23 2014 *)
    Select[Range[0,500],Intersection[IntegerDigits[#],{1,4,7}]=={}&] (* K. D. Bajpai, Sep 07 2014 *)
  • Python
    for n in range(10**3):
      s = str(n)
      if not (s.count('1') + s.count('4') + s.count('7')):
        print(n,end=', ') # Derek Orr, Sep 19 2014
    

Extensions

Corrected and extended by Rick L. Shepherd, May 21 2003
Offset corrected by Arkadiusz Wesolowski, Aug 15 2011
Definition clarified by Bernard Schott, Mar 25 2023

A034470 Prime numbers using only the curved digits 0, 2, 3, 5, 6, 8 and 9.

Original entry on oeis.org

2, 3, 5, 23, 29, 53, 59, 83, 89, 223, 229, 233, 239, 263, 269, 283, 293, 353, 359, 383, 389, 503, 509, 523, 563, 569, 593, 599, 653, 659, 683, 809, 823, 829, 839, 853, 859, 863, 883, 929, 953, 983, 2003, 2029, 2039, 2053, 2063, 2069, 2083, 2089, 2099, 2203
Offset: 1

Views

Author

Robert G. Wilson v, Jan 24 2003

Keywords

Comments

Intersection of A000040 and A028374. - K. D. Bajpai, Sep 07 2014

Examples

			From _K. D. Bajpai_, Sep 07 2014: (Start)
29 is prime and is composed only of the curved digits 2 and 9.
359 is prime and is composed only of the curved digits 3, 5 and 9.
(End)
20235869 is the smallest instance using all curved digits. - _Michel Marcus_, Sep 07 2014
		

Crossrefs

Programs

  • Maple
    N:= 4: # to get all entries with at most N digits
    S:= {0,2,3,5,6,8,9}:
    T:= S:
    for j from 2 to N do
    T:= map(t -> seq(10*t+s,s=S),T);
    od:
    select(isprime,T);
    # In Maple 11 and earlier, uncomment the next line:
    # sort(convert(%,list)); # Robert Israel, Sep 07 2014
  • Mathematica
    Select[Range[2222], PrimeQ[#] && Union[Join[IntegerDigits[#], {0, 2, 3, 5, 6, 8, 9}]] == {0, 2, 3, 5, 6, 8, 9} &] (* RGWv *)
    Select[Prime[Range[500]], Intersection[IntegerDigits[#], {1, 4, 7}] == {} &] (* K. D. Bajpai, Sep 07 2014 *)

A079652 Prime numbers using only the curved digits 0, 3, 6, 8 and 9.

Original entry on oeis.org

3, 83, 89, 383, 389, 683, 809, 839, 863, 883, 983, 3083, 3089, 3389, 3803, 3833, 3863, 3889, 3989, 6089, 6389, 6689, 6803, 6833, 6863, 6869, 6883, 6899, 6983, 8009, 8039, 8069, 8089, 8093, 8363, 8369, 8389, 8609, 8663, 8669, 8689, 8693, 8699, 8803, 8839
Offset: 1

Views

Author

Shyam Sunder Gupta, Jan 23 2003

Keywords

Comments

Intersection of A000040 and A072960. - K. D. Bajpai, Sep 01 2014

Crossrefs

Programs

  • Maple
    N:= 4: # to get all terms with up to N digits
    Digs:= {0,3,6,8,9}:
    A:= NULL:
    for d from 1 to N do
      C:= combinat[cartprod]([Digs minus {0},Digs $(d-1)]);
      while not C[finished] do
        L:= C[nextvalue]();
        x:= add(L[i]*10^(d-i),i=1..d);
        if isprime(x) then A:= A,x fi
      od
    od:
    A; # Robert Israel, Aug 31 2014
  • Mathematica
    Select[ Range[8850], PrimeQ[ # ] && Union[ Join[ IntegerDigits[ # ], {0, 3, 6, 8, 9}]] == {0, 3, 6, 8, 9} &]
    Select[Prime[Range[5000]], Intersection[IntegerDigits[#], {1, 2, 4, 5, 7}] == {} &] (* K. D. Bajpai, Sep 01 2014 *)
    Select[FromDigits/@Tuples[{0,3,6,8,9},4],PrimeQ] (* Harvey P. Dale, Sep 05 2022 *)

A082741 Numbers that have digits consisting only of line segments or both line segments and curves (base 10 digits are 1, 2, 4, 5, 7).

Original entry on oeis.org

1, 2, 4, 5, 7, 11, 12, 14, 15, 17, 21, 22, 24, 25, 27, 41, 42, 44, 45, 47, 51, 52, 54, 55, 57, 71, 72, 74, 75, 77, 111, 112, 114, 115, 117, 121, 122, 124, 125, 127, 141, 142, 144, 145, 147, 151, 152, 154, 155, 157, 171, 172, 174, 175, 177, 211, 212, 214, 215, 217, 221
Offset: 1

Views

Author

Rick L. Shepherd, May 21 2003

Keywords

Comments

This sequence allows the digits 2 and 5, formed from combinations of line segments and curves; the subsequence A028373 does not.

Crossrefs

Cf. A028373 (line-segment digits 1, 4, 7 only), A028374 (digits with curves or both curves and line segments), A072960 (curved digits 0, 3, 6, 8, 9 only).

Programs

  • Maple
    a:= proc(n) local d, i, m, r; m:=n; r:=0;
          for i from 0 while m>0 do
            d:= irem(m, 5, 'm');
            if d=0 then d:=5; m:=m-1 fi;
            r:= r+10^i*[1, 2, 4, 5, 7][d]
          od: r
        end:
    seq(a(n), n=1..100);  # Alois P. Heinz, May 25 2014
  • Mathematica
    Table[FromDigits/@Tuples[{1,2,4,5,7},n],{n,3}]//Flatten (* Harvey P. Dale, Apr 17 2022 *)

A214584 Integers whose decimal representation has only digits in {4,5,7}.

Original entry on oeis.org

4, 5, 7, 44, 45, 47, 54, 55, 57, 74, 75, 77, 444, 445, 447, 454, 455, 457, 474, 475, 477, 544, 545, 547, 554, 555, 557, 574, 575, 577, 744, 745, 747, 754, 755, 757, 774, 775, 777, 4444, 4445, 4447, 4454, 4455, 4457, 4474, 4475, 4477, 4544, 4545, 4547, 4554, 4555, 4557, 4574, 4575, 4577, 4744
Offset: 1

Views

Author

Jonathan Vos Post, Jul 21 2012

Keywords

Comments

These could be called crooked numbers. Integers all of whose numerals are written (san serif) with at least one right or acute angle. The subsequence of crooked primes begins: 5, 7, 47, 457, 547, 557, 577, 757.
Exponential density 0.477... = log 3/log 10. - Charles R Greathouse IV, Jul 22 2012

Crossrefs

Cf. A072960 (numbers using only the curved digits 0, 3, 6, 8 and 9).

A217048 Semiprimes using only the curved digits 0, 3, 6, 8 and 9.

Original entry on oeis.org

6, 9, 33, 38, 39, 69, 86, 93, 303, 309, 339, 386, 393, 398, 633, 669, 689, 698, 699, 803, 838, 866, 869, 886, 889, 893, 898, 899, 933, 939, 989, 993, 998, 3039, 3063, 3086, 3093, 3098, 3099, 3309, 3338, 3369, 3383, 3386, 3398, 3603, 3639, 3669, 3683, 3693
Offset: 1

Views

Author

Jonathan Vos Post, Sep 25 2012

Keywords

Comments

This is to A079652 as semiprimes A001358 are to primes A000040.

Examples

			a(41) = 3338 = 2 * 1669, the 938th semiprime.
		

Crossrefs

Programs

  • Magma
    IsSemiprime:=func; [n: n in [2..3700] | IsSemiprime(n) and Intseq(n) subset [0,3,6,8,9]]; // Bruno Berselli, Sep 25 2012
  • Maple
    R:= [0,3,6,8,9]:
    Res:= NULL: count:= 0:
    for m from 1 while count < 100 do
      L:= convert(m,base,5);
      n:= add(R[L[i]+1]*10^(i-1),i=1..nops(L));
      if numtheory:-bigomega(n)=2 then Res:= Res, n; count:= count+1 fi
    od:
    Res; # Robert Israel, Feb 16 2020

Formula

A001358 INTERSECTION A072960.

A361780 Numbers that have digits consisting only of line segments {1, 4, 7} or curved digits {0, 3, 6, 8, 9}.

Original entry on oeis.org

0, 1, 3, 4, 6, 7, 8, 9, 10, 11, 13, 14, 16, 17, 18, 19, 30, 31, 33, 34, 36, 37, 38, 39, 40, 41, 43, 44, 46, 47, 48, 49, 60, 61, 63, 64, 66, 67, 68, 69, 70, 71, 73, 74, 76, 77, 78, 79, 80, 81, 83, 84, 86, 87, 88, 89, 90, 91, 93, 94, 96, 97, 98, 99, 100, 101, 103, 104, 106, 107, 108, 109, 110
Offset: 1

Views

Author

Bernard Schott, Mar 23 2023

Keywords

Comments

This sequence allows all digits except for 2 and 5.

Crossrefs

Cf. A028373 (line-segment digits: {1, 4, 7}), A072960 (curved digits: {0, 3, 6, 8, 9}), A072961 (both line segments and curves digits: {2, 5}).
Cf. A082741 (digits: {1, 2, 4, 5, 7}), A028374 (digits: {0, 2, 3, 5, 6, 8, 9}), this sequence (digits {0, 1, 3, 4, 6, 7, 8, 9}).

Programs

  • Mathematica
    Select[Range[0, 110], AllTrue[IntegerDigits[#], ! MemberQ[{2, 5}, #1] &] &] (* Amiram Eldar, Mar 24 2023 *)

A079653 Triangular numbers using only the curved digits 0, 3, 6, 8 and 9.

Original entry on oeis.org

0, 3, 6, 36, 66, 300, 630, 666, 903, 990, 3003, 6903, 33930, 39060, 39903, 63903, 66066, 69006, 93096, 306936, 333336, 339900, 600060, 609960, 630003, 669903, 690900, 833986, 930930, 936396, 963966, 3036880, 3069003, 3083886, 3306306, 3689686, 3966336, 3988900
Offset: 1

Views

Author

Shyam Sunder Gupta, Jan 23 2003

Keywords

Crossrefs

Intersection of A000217 and A072960.

Programs

  • Mathematica
    t[n_] := n*(n + 1)/2; t /@ Select[Range[0, 10000], AllTrue[IntegerDigits[t[#]], MemberQ[{0, 3, 6, 8 , 9}, #1] &] &] (* Amiram Eldar, Aug 18 2020 *)

Extensions

a(1) = 0 and more terms from Amiram Eldar, Aug 18 2020

A079655 Perfect squares using only the curved digits 0, 3, 6, 8 and 9.

Original entry on oeis.org

0, 9, 36, 900, 3600, 3969, 6889, 8836, 38809, 69696, 80089, 90000, 93636, 339889, 360000, 363609, 380689, 396900, 660969, 688900, 693889, 698896, 883600, 896809, 988036, 3663396, 3869089, 3880900, 3988009, 6066369, 6086089, 6969600, 8008900, 8088336, 8803089
Offset: 1

Views

Author

Shyam Sunder Gupta, Jan 23 2003

Keywords

Crossrefs

Intersection of A000290 and A072960.

Programs

  • Mathematica
    Select[Range[0, 3000], AllTrue[IntegerDigits[#^2], MemberQ[{0, 3, 6, 8 , 9}, #1] &] &]^2 (* Amiram Eldar, Aug 18 2020 *)

Extensions

More terms from Amiram Eldar, Aug 18 2020

A079656 Cubes using only the digits 0, 3, 6, 8 and 9.

Original entry on oeis.org

0, 8, 8000, 3869893, 8000000, 3869893000, 3996969003, 8000000000, 99060039883, 339630096833, 630966396033, 688933306368, 869889903336, 3869893000000, 3996969003000, 8000000000000, 63836938680696, 99060039883000, 339630096833000, 630966396033000, 688933306368000
Offset: 1

Views

Author

Shyam Sunder Gupta, Jan 23 2003

Keywords

Crossrefs

Programs

  • Mathematica
    Do[ If[ Union[ Join[ IntegerDigits[n^3], {0, 3, 6, 8, 9}]] == {0, 3, 6, 8, 9}, Print[n^3]], {n, 0, 50000}]

Extensions

More terms from Robert G. Wilson v, Jan 24 2003
Showing 1-10 of 13 results. Next